Counting the days when you don't actually know the day you are counting down to!

This is what I am doing at the moment.
Obviously there are the big days like Christmas day and New Years day, but there are also the not so International count downs, for instance
The double Baptism             -One day.
The Dentist!!                        -Twelve days.
The Farrier                           -Thirty five days.
The charity coffee morning -Forty three days.
But just when the Northern bird is going to fly south for a visit is a complete mystery!